The present invention relates generally to vehicle seat assemblies and in particular to seat assemblies including an integral seat belt restraint systems and a dump feature for the seat back.
Vehicle seat belt systems are typically mounted directly to a vehicle structure. For example, many belt systems have a webbing retractor mounted to the vehicle floor pan with the webbing extending upward, along the B-pillar of the vehicle, to a D-ring mounted to the pillar near its upper end. The webbing then extends downward to an end connected to the floor pan adjacent to the retractor. A clasp is slidably movable along the webbing between the attached end and the D-ring. A buckle is attached to the vehicle floor on the opposite side of a seat assembly. When the clasp is pulled across the seat occupant and inserted into the buckle, the webbing forms a lap belt and a shoulder belt to retain the occupant in the seat assembly.
The position of a front seat assembly in a motor vehicle is adjustable relative to the vehicle interior in at least the fore and aft direction and, in some seat assemblies adjustable in other directions as well. With movement of the seat assembly relative to the vehicle, there is also movement of the seat assembly relative to the seat belt system. This relative movement can result in the belt system becoming inconvenient and/or uncomfortable to use. To improve both the comfort and convenience of using a seat belt, seat assemblies are now being designed which incorporate the seat belt system directly into the seat assembly. This ensures that regardless of the position of the seat assembly relative to the vehicle, the seat belt system will remain in one position relative to the seat occupant. Such a seat assembly is often referred to as an integrated structural seat assembly in that the seat belt system has been integrated into the seat assembly. An integrated structural seat has a further advantage of facilitating the assembly of the motor vehicle. Instead of attaching separate restraint system components to the vehicle structure at various locations and also attaching a seat assembly to the vehicle floor pan, the vehicle assembler will only need to attach the integrated structural seat to the vehicle structure.
However, the integrated structural seat must also carry the additional seat belt load during a vehicle collision. As a result, the structural frame of an integrated seat must be significantly increased in its strength to accommodate the increased load. The present invention is related to a dump feature provided in an integrated seat for releasing the seat back, allowing the seat back to be rotated to a forwardmost "dump" position to facilitate access to the rear seat area of a two-door motor vehicle. In an integrated seat assembly with the shoulder restraint belt attached to the seat back, it is necessary that the latch for the seat back dump mechanism be sufficiently strong to accommodate the shoulder belt loads. In addition, it is also necessary that when the seat back is returned from the dump position, latching of the seat back is assured.
Accordingly, it is an object of the present invention to provide a seat back dump mechanism which is able to accommodate the shoulder belt loads and also to ensure latching upon return of the seat back to its operative use position.
It is a further object of the present invention to provide such a dump feature in a seat assembly having a power seat back recliner mechanism.
A power recliner mechanism is typically designed so as to be continuously engaged to hold the seat back in place. Thus, to provide a dump mechanism in a seat assembly with a power recliner, it is necessary that the dump mechanism operate separately from the continuously engaged power recliner.
The seat assembly includes a fore and aft slide track to which the seat cushion and seat back are both mounted. The seat back is mounted for rotation about a transverse axis. The power recliner includes a threaded lead screw with a first end pivotally connected to the slide track and a spin nut threadably engaging the lead screw and captured within a drive housing that is pivotally coupled to the seat back frame. A motor is provided for driving the spin nut along the length of the lead screw affecting the distance between the drive housing coupled to the seat back frame and the connection of the lead screw to the slide track. This results in an angular adjustment of the seat back position.
Seat back dumping is enabled by a latch mechanism which releasably couples the lead screw to the seat track. Upon release of the latch mechanism, the seat back is free to rotate to a forward dump position. Upon return of the seat back to its use position, the lead screw is latched to the slide track, fixing the seat back in place. The latch uses a toggle mechanism to latch and release the lead screw to and from the slide track. While the dump mechanism of the invention is described in the context of a power recliner, it can be utilized with a manual recliner to provide a dump mechanism with full position memory.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.